This new cultivar of Zelkova serrata, the ‘JSC Kingsthree’ zelkova, originated as a single seedling that was discovered by James David Cavett in 2005 in a group of Zelkova serrata planted in a field on the nursery of James D. Cavett at 74 S & W Lane, Estill Springs, Tenn. 37330. James D. Cavett grafted four buds from the new cultivar, ‘JSC Kingsthree’ onto Zelkova serrata seedlings in 1-gallon containers at 74 S&W Lane, Estill Springs, Tenn. 37330 in July 2005. Two of the 4 grafted seedlings survived. In February 2007, a second generation of sixty-five grafted seedlings were started from these 2 surviving grafted seedlings. Exactly 63 of the grafted seedlings begun in February 2007 survived and were used to begin a third generation of 250 new grafted seedlings in February 2008. Two-hundred of these 250 new grafted seedlings survived. In February 2009, approximately 500 grafted ‘JSC Kingsthree’ seedlings were taken and grafted onto Zelkova serrata seedlings; approximately 350 emerged and survived. In February 2009, rooted cuttings were also used to grow the new Zelkova serrata cultivar. In February 2009, 150 rooted cuttings were taken from the new ‘JSC Kingsthree’ Zelkova serrata cultivars and rooted in sand using indole-3-butyric acid at 74 S&W Lane, Estill Springs, Tenn. 37330, and 100 survived. In June 2009, 1500 additional rooted cuttings were begun, and 1200 survived. In July 2009, 6000 additional rooting cuttings of ‘JSC Kingsthree’ were begun, and 4500 survived. Over the last four years, all of the grafted seedlings and rooted cuttings of ‘JSC Kingsthree’ have exhibited several different growing characteristics and patterns than the parent plant Zelkova serrata as well as differences in leaf pigmentation, leaf shape (it curls around itself), and leaf texture. Furthermore, the branches of the new ‘JSC Kingsthree’ cultivars exhibit a weeping growth pattern; whereas, traditional Zelkova serrata do not weep. At the end of many branches of the ‘JSC Kingsthree’, the branch makes a 30 to 60-degree bend at a leaf bud (See FIG. 2). When the leaves first emerge from their apical meristems, they are reddish-brown (RHS #171A [when further referring to the coloring of the specimen, the RHS color designation is derived from The 2005 R.H.S. Mini Colour Chart]). They quickly become light green for 2 to 3 weeks, turning dark green as they mature. The upper side of young leaves (three-week-old leaves) is (RHS #137A); the color of the upper side of the most mature leaves is dark green (RHS #136A). The color of the lower side of the immature leaf is a light green (RHS #141D), but changes in the most mature leaves to a darker green (RHS #144A). During fall, the margin of the leaf becomes reddish-brown (RHS #171A) and the leaf along the main vein changes from a light yellow-brown (RHS # 163B) to a reddish-brown (RHS #171A). From the emergence of the leaves from the bud, both new growth and mature leaves curl along the axis of the main vein that differs from the leaf of the parent plant. Another characteristic of the ‘JSC Kingsthree’ leaves that differs from the parent plant is that both new growth and mature leaves have a “velvet” texture because of tiny hairs located on the lower and upper epidermis of the leaf. The branches of the ‘JSC Kingsthree’ cultivar weep unlike the parental Zelkova serrata. Also, the terminal end of many branches makes a 90-degree angle at a distal leaf axis (see FIG. 6). James D. Cavett has been evaluating these grafted seedlings for four years and evaluating the rooted cuttings for one year.
James D. Cavett is solely responsible for finding this new cultivar, known as ‘JSC Kingsthree’, on his property located at 74 S&W Lane, Estill Springs, Tenn. 37330. All grafted seedlings and rooted cuttings of this cultivar have been done by James D. Cavett at his nursery located at 74 S&W Lane, Estill Springs, Tenn. 37330.
James D. Cavett immediately recognized that the new cultivar ‘JSC Kingsthree’ exhibited new and distinctive leaf pigmentation, leaf shape (curling around the main leaf vein), leaf sculpturing, leaf texture, branch structure, and growth pattern. The leaves are reddish-brown (see FIG. 3) when they first emerge from the bud and, within the first 3 weeks, the leaf exhibits a light green pigmentation. As the leaf enlarges and matures; however, the leaf pigmentation becomes dark green. The mature leaf is dark green in color. Only the seedlings that have originated from the grafted or rooted seedlings of the newly discovered cultivar, known as ‘JSC Kingsthree’, exhibit these new characteristics that are distinctively different from the parental Zelkova serrata from which it originated as well as differs from all known Japanese Zelkova trees by exhibiting its unique leaf curl, branch structure and leaf texture which are not found in any other known species of Zelkova. Another difference between the ‘JSC Kingsthree’ cultivar and the ordinary Zelkova serrata is the presence of trichomes all over the upper and lower surfaces of the leaves as well as on the petioles (see FIG. 5). In the Zelkova serrata, trichomes are not visibly present. The leaf shape also differs between the ‘JSC Kingsthree’ and Zelkova serrata cultivars in that the leaf of the ‘JSC Kingsthree’ has a prominent curl along the axis of the main leaf vein (see FIG. 7). There is no such curl present in the regular Zelkova serrata. Finally, the branches of the ‘JSC Kingsthree’ differ in several ways from the parent Zelkova serrata plant: first the limbs grow at a 30 to 60-degree angle (see FIGS. 1 and 2), and at the terminal end of some of the limbs, there is a 90-degree bend in the limb (see FIG. 6). Neither of these are characteristics present in Zelkova serrata. Over the last 4 years, both the grafted seedlings and rooted cuttings have exhibited this pigmentation, leaf curling, leaf texture, and branch structure as compared to other Zelkova serrata trees.
The ‘JSC Kingsthree’ cultivar has proven to be both drought resistant and very winter hardy. In April 2007, Middle Tennessee (climate Zone 6b, USDA Plant Hardiness Zone Map) experienced an unusually late freeze during which the overnight temperatures dropped into the low 20's F. This was a particularly dangerous and damaging freeze because most of the trees had already budded. The ‘JSC Kingsthree’ cultivar survived this freeze and continued to produce foliage throughout the spring and summer months. All grafted seedlings and rooted cuttings taken from the plants exhibit the same moderate growth that has been observed for the last 4 growing seasons that the ‘JSC Kingsthree’ cultivar has been cultivated.
The ‘JSC Kingsthree’ cultivar can also endure drastic fluctuations in moisture. ‘JSC Kingsthree’ cultivar has been successfully grown without irrigation after it is moved into the fields during its second season. Each summer since it was grafted in 2004, it has endured the drought that Middle Tennessee has experienced during the months of July and August. Middle Tennessee usually experiences heavy rainfalls during the spring; however, immediately after the late spring 2007 freeze, another unusual meteorological event occurred; Middle Tennessee experienced an early 2-month drought. While many annuals, perennials, shrubs, and trees were severely damaged or killed by the late spring freeze that was followed by a 2-month drought, the ‘JSC Kingsthree’ cultivar survived and demonstrated itself to be cold and drought tolerant.
The ‘JSC Kingsthree’ cultivar has been successfully grafted asexually. The proven means of asexual propagation has been rooted softwood cuttings and grafting. In 2005, when the new cultivar was discovered by James D. Cavett, four buds were removed and grafted onto Zelkova serrata seedlings planted in a one-gallon container located at 74 S&W Lane, Estill Springs, Tenn. 37330, and two survived. In February 2007, 65 grafted cultivar seedlings were started from the two surviving ‘JSC Kingsthree’ seedlings that had been grafted 2005, and 63 survived. In February 2008, 200 of 250 grafts taken from the other ‘JSC Kingsthree’ trees were grafted and survived. In February 2009, 500 grafted seedlings were taken from the ‘JSC Kingsthree’ trees and grafted onto the Zelkova serrata seedlings; approximately 350 survived grafted seedlings survived. In February 2009, 150 rooted cuttings were started and 100 survived. In June 2009, 1500 rooted cuttings were started and 1200 survived. In July 2009, an additional 6000 rooted cuttings were started and 4500 survived. The cultivars (both grafted seedlings and rooted cuttings) have retained all the characteristics of the original selected seedling, the cultivar known as ‘JSC Kingsthree’. The ‘JSC Kingsthree’ cultivar has been successfully grafted through 4 generations of asexual reproduction with a survival rate of 97% during the second year (2007), 80% during the third year (2008), and 70% during the fourth year (2009) for grafted seedlings. The survival rate of the rooted cuttings approximates the survival rate of grafted seedlings. The rooted cuttings that were begun February 2009 had a survival rate of 66%; the June 2009 rootings had a survival rate of 80%, and the July 2009 cuttings had a survival rate of 75%. Every generation of the ‘JSC Kingsthree’ cultivar that has been asexually propagated has been stable and produced true-to-type plants.
The unique color, shape and texture of the leaves, growth pattern, branching structure and moderate growth (3 to 4 feet per year) of the ‘JSC Kingsthree’ cultivar make it well suited for a variety of landscaping uses. Furthermore, the ‘JSC Kingsthree’ cultivar is cold and drought tolerant. The cultivar is a moderate size tree whose leaf pigmentation changes from light green to dark green. For the first three weeks after the leaf emerges from its bud, it is reddish-brown in color; however, as the leaf enlarges, the pigmentation becomes a dark green color, the color of the mature leaf. The dark green color of the leaves of the ‘JSC Kingsthree’ cultivar will make it a hardier zelkova for those who desire an attractive landscaping tree. In the fall the leaves turn from a dark green to a mixture consisting of reds, maroons, and yellow-browns. Some of the leaves of the ‘JSC Kingsthree’ cultivar also exhibit a pronounced curl along the leaf's main vein, and all leaves exhibit a velvet texture, which differs from the straight, flat leaf of the Zelkova serrata. The petiole of the leaf has an extremely large number of trichomes, which in the correct lighting conditions (early morning or late afternoon) cause the tree to appear to be covered with frost. Finally, the limbs follow a different growth pattern than that of the Zelkova serrata. The branches “bend” or “droop” at approximately 30 to 60 degrees in the middle of the growing branch, which does not occur in the general Zelkova serrata. Continued branch growth after this bend occurs results in the weeping appearance of the tree. There is also a distinct bend near the terminal end of some branches, where the branch growth changes direction and grows out at a 90° angle, which does not occur in any Zelkova serrata. After this time period it exhibits relatively normal growth pattern as compared to the Zelkova serrata, except that it has a fuller canopy, and its limbs do not grow as upright as the Zelkova serrata. 